Electric heating apparatus.



F. THORNION, In,

ELECTRIC HEATING APPARATUS.

APPLICATION FILED APII. I2. I9I5\ 1,241,578. PaIenIed Oct. 2, '1917.

2 SHEETS--SHEET I.

Fran/f Hor/7 fon, J/f

4 BY www ATTOFIINEY F. THORNTON, JA.

ELECTRIC HEATING APPARATUS.

APPLICATION FILED APR. i2. |915- Pamented Oct 2,1917.

2 SHEETS-SHEET 2 WITNESSES N, wm T0 Nf we mM H, m f F ATTORNEY I lNlTEDSTATES PATENT FFGE.

FRANK THORNTON, JR., OF PITTSBURGH, PENNSYLVANIA, AS-SGNOR T0 'WESTINGK-H'SE ELECTRIC AND MANUFCTURNG COM?ANY, A CAORPORATON 0F .'ENNSYL-ELECTRIC HEATXNG APPARATUS.

Application e April 12, 1915.

To all whom 't may concern.'

Be it known that l, FRANK THORNTON, Jr., a citizen of the United States,and a resident of Pittsburgh, in the county of Allegheny and State ofPennsylvania, have invented a new and useful Improvement in ElectricHeating Apparatus, of which the following is a specification.

My invention relates to electric heatlng apparatus and it has specialreference'to heating devices of the radiant type in which a heatingelement is mounted upon a support of insulating material in contact withthe air to impart its heat by radiation.

The object of my invention is to provide a simple and inexpensive methodof mounting conducting wires or ribbons upon insulating supports.

More specifically, the object of my invention isto provide a method ofmounting resistance elements upon insulating sheets formed offragmentary insulating material, such as flakes of mica, and a furtherobject of my invention is to provide a radianttype electric toasterstove having a heating element constructed in accordance with the methodindicated above.

In the accompanying drawings, Figure 1 is a side elevational view of atoaster stove constructed in accordance with my invention. Fig. 2 is anend elevational View of the device shown in Fig. 1 taken from vthe rightof Fig. 1, and F 1g. is a transverse central sectional view of the samedevice.

The device shown on the drawing consists .of arectangular heating plate1 mounted in a substantially vertical position in a frame composed ofend pieces 2 and 3 joined by a top plate 4 and a bottom plate 5, the endpieces 2Q and 3 being bent outwardly and downwardly to form supportinglegs l6. The bottom plate is curved downwardly, as shown in Fig. 3, toform a crumb collector. llVires 7 are disposed on both sides of theheating element 1 and are bent into the form shown for the purpose ofsupporting slices of bread or the like to be toasted. The ends of thewires 7 may be received in perforations in the bottom plate 5, and thebent centralportions of the wires are supported in clamps formed bycutting slots in the top plate 4 and bending the cut por- Spec'eatlon ofLetters Patent.

Fatented Got. tt?.

Serial No. 20,895.

tion of the metal into ears 8 and 9. A metal fastened to the top plate 4by means of rivets 11. A terminal block holder 12 is riveted to the endplate 3 andcontains a terminal block 13 of any suitable form. The holder12 is formed into a receptacle 14 adapted to receive a terminal block15.

The structural details thus far described are merely illustrative andare not essential to my invention, which is concerned particularly withthe structure of the heating element 1. This element is composed of arectangular metal frame 16 provided with ears 17 at its-four cornerswhich are adapted to project through openings in the end pieces 2 and 3of the toaster frame. A rectangular plate 18, composed of built-up micaflakes, is mounted in the frame 16 and is provided with spaced rows ofperforations 19 through which is passed a resistance wire or ribbon 20,the ends of which are led to the terminal block 13 through a oord 21.

lt will be observed that three transverse rows of resistance v'stripsare provided on each side of the plate 18 and that the lowest row of thethree consists of a greater number of strips than the two upper rows.This is a desirable arrangement because it affords increasedheat-radiating capacity adjacent to the lower portions of 'the slices ofbread that may be supported on the rack formed by the wires 7, whichportions ot the bread are farther away from the heating element than theupper portions.

ln making the heating element, a composite plate is iirst formed fromsmall Hakes of mica held together by a bonding material that cansubsequently be driven cti by heating. This composite plate is mountedin the frame 16 and perforated in the manner shown, and theresistancewire or ribbon is :around on 'the sheet of mica b lacing itthrough the corresponding pertorations in the several rows. The plate isthen heated to a suiiicient temperature to evaporate the bondingmaterial, leaving the heater consisting only of the mica and theresistance material. The method of winding the resistor by lacing itthrough the holes results in holding the smallpieces of mica in theirproper positions after the bonding material has been driven 0H. In allsimilar structures that have heretofore been devised, it has beennecessary to provide solid sheets of natural mica of the necessary area,and such sheets are relatively expensive. It Will be evident that mymethod of mounting resistors, in which the resistor is supported by thecomposite insulating material and also serves to hold the. insulatingmaterial in its assembled position, results in a considerable saving inexpense.

The principles of my invention may be applied to many forms of devicesother than radiant toaster stoves, and it is also to be understood thatfragmentary insulating mate rial other than mica may be used Within thescope of my invention. I desire, therefore, that no limitations beimposed upon my invention unless indicated i in the appended claims.

I claim 'as my invention:

l. The method of mounting electric conductors upon insulating supportsthat comprises uniting a fragmentary insulating material into a:coherent structure by means of a binder, mounting a body of conductingmaterial on the said structure, and removing the said binder.

2. The method ofmounting electric conductors upon insulating supportsthat comprises uniting flakes of mica into a coherent structure by meansof a binder, mounting a body of conducting material on the saidstructure and removing the said binder.

3. The method of mounting electric conductors upon insulating supportsthat com prises uniting Hakes of mica into a coherent structure by meansof a binder, mounting a body of conductingmaterial upon the saidstructure in such a manner as to hold the flakes together, and removingthe said binder.

4. `The method of mounting electric conductors upon insulating supportsthat comprises forming a composite sheet of a fragmentary insulatingmaterial and a binder, perforating the said sheet, passing a body ofconducting material through the perforations in the said sheet, andremovingthe said binder; Y

5. The method of mounting electric con duetors upon insulating supportsthat comprises forming a composite sheet Vof mica Hakes and a binder,perforating the said sheet, passing a body of conducting materialthrough the perforations in the said sheet, and removing the saidbinder. v

6. The method of mounting electric conductors upon insulating supportsthat comprises forming a composite sheet of mica flakes and ahinder'that can be subsequently removed by heat, perforating the saidsheet, passing a body of conducting material through the perforations inthe said sheet, and heating the resulting structure to remove the saidbinder.

7. The process of making resistance devices for electric heatingapparatus and the like that comprises forming a composite sheet of afragmentary insulating material and a binder, forming a plurality ofspaced perforations in the vsaid sheet, passing a resistance Wirethrough the said perforations in such a manner that the resistance wireis supported by the said sheet and also serves to maintain thefragmentary material in its assembled position, and removing the saidbinder.

8. The process of making resistance devices for electric heaters and thelike that comprises forming a composite sheet of mica Hakes andavaporizable binder, forming a plurality of spaced perforations in thesaid sheet, passing a resistance Wire through the said perforations insuch a manner that the resistance wire is supported by the said sheetand also serves to maintain the mica Hakes in their assembled position,and applying heat to volatilize the said binder.

9. The process of making resistance devices for electric heaters and thelike that comprises forming a composite sheet of mica Hakes and abinder, forming a plurality of rows of perforations 1n the said sheet,

passing a resistance Wire back and forth through the correspondingperforations in the said rows in such a manner that the resistance wireis supported by the said sheet and also serves to hold the said micaHakes together, and removing the said binder.

10. An electric heating device comprising a composite structure offragmentary insulating material held in assembled position by means of aresistance element, the said resistance element being supported upon thesaid structure and extending therethrough in a plurality ofconvolutions.

11. An electric heating device comprising a sheet composed of micaflakes held t0- gether by means of a resistance element supported uponthe said structure and extending therethrough in a plurality' ofconvolutions l2. An electric heating device comprising a composite sheetof mica flakes rovided with av plurality of rows of perforations, and aresistance Wire extending back and forth through the correspondingperforations in the said rows in such manner that the said resistanceWire is supported by the said sheet and also holds the said Hakestogether.

13. A radiant electric toaster device comprising a frame, a radiantresistance device supported therein and a terminal device for supplyingenergy to the said resistance device, the said resistance devicecomprising a composite sheet of mica Hakes provided with a plurality ofrowsof perforations and a remerma S sistance wire extending back andforth resistance conductor extending through perthrough thecorresponding perforations in forations in the sheet and supportedthereby l@ the said rows in such manner that the said to presentradiating surfaces on both sides resistance wire is supported by thesaid sheet of the said sheet. 5 and also holds the said flakes together.In testimony whereof, I have hereunto sub- 14. An electric heatingdevice comprising scribed my name this 30th day of March, n frame, asheet of insulating material sup 1915.

ported vertically by the said frame, and a FRANK THORNTON, JR.

